Spontaneous muscle infarction is a rare complication of diabetes mellitus, mainly affecting women and patients with long-lasting type 1 diabetes. This report is aimed to describe the case of a patient with type 1 diabetes and diabetic nephropathy in whom a severe deterioration of renal function was triggered by a muscle infarction. Subject of the study was a 33-years-old woman with an 18 years history of type 1 diabetes mellitus, proliferative diabetic retinopathy, nephropathy at stage 3 chronic kidney disease, somatic sensory-motor polyneuropathy and autonomic neuropathy. The patient presented with severe pain and dysfunction of the left thigh without prior trauma plus progressive deterioration of the renal function. Nuclear magnetic resonance of the thigh showed inflammatory changes in the external vastus with hyperintensity on T2 sequence and edema of the subcutaneous cellular tissue. After other possible etiologies were ruled out, a clinical diagnosis of spontaneous muscle infarction was established. The patient needed hospital admission for two months, during which the renal function worsened until she required hemodialysis. No other possible triggers of kidney injury were identified. Up to our knowledge, this is the first described case where muscle infarction is suspected to have caused exacerbation of an existing chronic kidney failure. Monitoring the renal function should be considered in patients with diabetic nephropathy presenting with this rare complication of diabetes.